An earthquake has hit Adelaide this morning, with thousands of people within 100km of the CBD reporting the tremor.
Geoscience Australia said the magnitude-3.8 tremor was recorded near Mt Barker in the Adelaide Hills at 7:20am.
A magnitude-2.5 aftershock was recorded at 9am around the Mt Barker area.
Reports on the Geoscience Australia website show the first tremor was felt as far as Waterloo in the north, all the way to Encounter Bay in the south.
Phil Cummins, senior seismologist at Geoscience Australia, said while the earthquake was strong enough to be felt, it would not have caused major damage.
"That's certainly significant in terms of being felt," he said.
"Anyone close to that earthquake could feel that, but I would say it's unlikely to cause any substantial damage.
People have taken to social media to report being woken up by a small amount of shaking and rumbling, but police and the State Emergency Service say there are no reports of damage.
One Twitter user based in Adelaide said it felt like "more than a little shake".
Dr Cummins said the earthquake was "relatively shallow", but it would have been felt by people in Mount Barker as a "sharp initial wave" followed by a swaying motion.
The tremor was reported as 10km deep, but Dr Cummins said that was the figure usually given for shallow earthquakes, so it was not precise.
Dr Cummins said SA generally experienced a greater number of earthquakes than most other places in Australia.
He said there had been more than 100 tremors within 100km of Mount Barker over the last century, but most were smaller than magnitude-3.8.
The Bureau of Meteorology said there was no tsunami threat from the earthquake.
